Electromagnetic flowmeter having removable liner

ABSTRACT

An electromagnetic flowmeter having a meter pipe of magnetic material terminating at either end in a coupling flange. Coils are disposed within the pipe to establish an electromagnetic field which is mutually perpendicular to the longitudinal axis of the pipe and to a diametrical axis extending between a pair of electrodes mounted on the pipe. Telescopically insertable within the pipe is a replaceable liner assembly including a relatively rigid sleeve of non-magnetic material having a flange at only one end thereof which, when the sleeve is inserted, abuts the face of the corresponding flange in the meter pipe. Concentrically disposed within the sleeve is a tubular liner of resilient insulating material. The liner is provided at one end with a first flange abutting the face of the sleeve flange, and a second flange at the other end thereof, which when the assembly is in place, is adapted to abut the face of the corresponding pipe flange. The liner is bonded to the inner wall of said sleeve except at the end portion thereof which includes said second flange, whereby by temporarily collapsing the unbonded portion of the liner, the assembly may be readily telescoped within the pipe.

United States Patent Mannherz et al.

[ 51 Oct. 3, 1972 [54] ELECTROMAGNETIC FLOWMETER HAVING REMOVABLE LINER[72] Inventors: Elmer D. Mannherz, Southampton; Henry M. Hermanns,Huntingdon Valley, both of Pa.

[73] Assignee: Fischer & Porter Co., Warminster,

[22] Filed: May 28, 1971 [21] Appl. No.: 147,827

[52] US. Cl ..73/194EM, 138/140 [51] Int. Cl ..G0lf 1100, 601p 5/08 [58]Field of Search ..73/194 EM; 138/140, 147

[56] References Cited UNITED STATES PATENTS 2,088,922 8/1937 Porteous..138/140 X 3,334,518 8/1967 Miyamichi ..73/194 EM FOREIGN PATENTS ORAPPLICATIONS 187,344 2/1967 U.S.S.R. ..73/194 EM PrimaryExaminer-Charles A. Ruehl Attorney-Michael Ebert ABSTRACT Anelectromagnetic flowmeter having a meter pipe of magnetic materialterminating at either end in a coupling flange. Coils are disposedwithin the pipe to establish an electromagnetic field which is mutuallyperpendicular to the longitudinal axis of the pipe and to a diametricalaxis extending between a pair of electrodes mounted on the pipe.Telescopically insertable within the pipe is a replaceable linerassembly including a relatively rigid sleeve of non-magnetic materialhaving a flange at only one end thereof which, when the sleeve isinserted, abuts the face of the corresponding flange in the meter pipe.Concentrically disposed within the sleeve is a tubular liner ofresilient insulating material. The liner is provided at one end with afirst flange abutting the face of the sleeve flange, and a second flangeat the other end thereof, which when the assembly is in place, isadapted to abut the face of the corresponding pipe flange. The liner isbonded to the inner wall of said sleeve except at the end portionthereof which includes said second flange, whereby by temporarilycollapsing the unbonded portion of the liner, the assembly may bereadily telescoped within the pipe.

9 Claims, 7 Drawing Figures PATENTEDIIBI3 1912 3595,104

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I -q- INVENTORS ELECTROMAGNETIC FLOWMETER HAVING REMOVABLE LINERBACKGROUND OF THE INVENTION This invention relates generally toelectromagnetic flowmeters, and in particular to a replaceable linerassembly for a magnetic flowmeter.

The magnetic flowmeter is adapted to measure volume rates of thosefluids which present difficult handling problems, such as corrosiveacids, sewage, slurries, detergents, and the like. In a magneticflowmeter, a uniformly distributed magnetic field is generated which ismutually perpendicular to the longitudinal axis of the meter pipethrough which the fluid flows and to the axis of the meter electrodes.Since the velocity of the fluid is directed along the longitudinal axisof the pipe, the voltage induced within the fluid will be perpendicularto both the velocity of this fluid and the flux linkages of the magneticfield. Thus the metered fluid constitutes a series of fluid conductorsmoving through the magnetic field. The more rapid is the rate of flow,the greater the instantaneous value of the voltage established at theelectrodes.

One well-known flowmeter which is in widespread commercial use, makesuse of a flanged stainless steel pipe section, the inner wall of thepipe and the flange surfaces being lined with an insulating material.Two electrodes are mounted at diametrically opposed positions on thecentral portion of the pipe section, the electrodes being completelyinsulated from the pipe by bushings. The end surfaces of the electrodesare flush with the inner surface of the insulating liner and come incontact with the fluid to be metered. A field coil assembly is providedconsisting of two saddle-shaped magnet coils surrounded by a box-shapedlaminated iron core, which in turn completely encompasses the centralportion of the flowmeter. The field coil assembly is designed to producea linear and uniform magnetic field through the metering section.

The instantaneous voltage developed across the meter electrodesrepresents the average fluid velocity of the flow profile passing theelectrodes at a .given moment, and the flowmeter will produce an outputsignal equal to a continuous average flow rate regardless of whether theflow profile is laminar or turbulent. The flowmeter output signal islinearly proportional to the volumetric rate of flow through it.

It has heretofore been the practice to provide insulating linersfabricated of Teflon, neoprene, rubber or vitreous enamel, depending onthe anticipated nature of the fluid to be measured. While such linermaterials are satisfactory for many fluids, in those instances in whichthe flowmeter is intended to measure the flow rate of fluids which arehighly corrosive, the liner may fail after a fairly short period ofoperation. Moreover, the fluids may contain abrasive particles ofvarious sizes tending to score or mutilate the liner, making itnecessary to replace the liner.

Thus in an installation having a conventional magnetic flowmeter, whenthe insulating liner is worn away or degraded by abrasive particles orby other properties of the fluid being measured, the present practice isto return the flowmeter to the factory for disassembly, repair andrelining. This procedure has obvious disadvantages, for not only is ittime-consuming and costly,

but it also makes it necessary either to shut down the process or tosubstitute for the flowmeter undergoing repair, a temporary replacement.

SUMMARY OF THE INVENTION In view of the foregoing, it is the main objectof this invention to provide an electromagnetic flowmeter whichincorporates a replaceable liner assembly,

whereby a worn or defective liner may be removed and quickly replaced onthe job site.

More specifically, it is an object of the invention to provide areplaceable liner assembly insertable in a flanged meter pipe andconstituted by a non-magnetic sleeve of relatively rigid material havinga flange at one end only, and a tubular liner of resilient materialconcentrically disposed within the sleeve, the liner having a firstflange at one end which abuts the corresponding sleeve flange, and asecond flange at the other end which, when the assembly is in place, isadapted to abut the corresponding flange of the meter pipe.

The salient advantage of a liner assembly in accordance with theinvention is that it may be quickly removed from the meter on the jobsite and replaced by a fresh assembly, so that little operating time islost, thereby obviating the need to return the entire meter to thefactory for liner replacement and avoiding the expenses entailed in afactory replacement procedure.

Briefly stated these objects are attained in a flowmeter having a meterpipe of magnetic material, terminating at either end in a couplingflange, whereby the meter pipe may be interposed in a line conducting afluid to be measured. Coils are interposed within the pipe to establishan electromagnetic field therein which is mutually perpendicular to thelongitudinal axis of the pipe (the direction of fluid flow), and to adiametrical axis extending between a pair of electrodes mounted on themeter pipe.

Telescopically insertable within the pipe is a replaceable linerassembly including a relatively rigid sleeve of non-magnetic material,which covers the coils in the pipe but in no way interferes with themagnetic field established thereby, the sleeve having a flange at onlyone end thereof which, when the sleeve is fully inserted in the pipe,abuts the corresponding pipe flange.

Concentrically disposed within the sleeve is a tubular liner ofresilient insulating material having a first flange at one end thereofabutting the face of the sleeve flange, and having a second flange atthe other end which, when the assembly is in place, is adapted to abutthe face of the corresponding pipe flange. The liner is bonded to theinner wall of the sleeve, except at the end portion thereof whichincludes the second flange, whereby by temporarily collapsing saidunbonded portion of the liner, the assembly may be readily telescopedwithin the pipe.

OUTLINE OF THE DRAWING For a better understanding of the invention aswell as other objects and further features thereof, reference is made tothe following detailed description to be read in conjunction with theaccompanying drawing, wherein:

FIG. 1 is a cut-away perspective view of an electromagnetic flowmeter ofa prior-art type;

FIG. 2 illustrates in longitudinal section the meter body of a flowmeterin accordance with the invention;

FIG. 3 is a sectional view of a replaceable liner assembly in accordancewith the invention, which assembly is telescopable within the meter bodyshown in FIG. 2;

FIG. 4 shows, in section, the liner assembly inserted in the meter body;

FIG. 5 is a perspective view of the tool used to effect insertion of theassembly in the meter body;

FIG. 6 is an enlarged section of a portion of the inserted linerassembly and meter body; and

FIG. 7 illustrates, in section, one electrode in a flowmeterincorporating the liner assembly.

DESCRIPTION OF THE INVENTION Referring now to FIG. 1, there is shown aprior-art electromagnetic flowmeter which when modified in the manner tobe described, is adapted to receive a liner assembly in accordance withthe invention. The meter includes a generally cylindrical pipe 10,serving as the meter body. Pipe 10 is provided at either end withannular flanges 11 and 12, whereby the meter may be interposed in a pipeline conducting a fluid to be mea sured.

Disposed within a cylindrical recess 13 formed within the meter body area pair of saddle-shaped electromagnetic coils l4 and 15 which areembedded in a potting compound. In practice this compound may be afilled mixture of an epoxy-based material. The coils act to establish amagnetic field extending at right angles to the diametrical axis passingthrough a pair of electrodes 16 and 17 connected to the output terminalsof the meter.

The interior of the pipe is lined with a tubular liner 18 ofpolyurethane, Teflon, neoprene or rubber, terminating at either end inflanges l9 and 20 which abut the faces of body flanges l 1 and 12,respectively.

In other known forms of flowmeters, the magnetic field coils are placedoutside of the meter body. However in the meter design shown in FIG. 1,the coils 14 and 15 which generate the magnetic field, lie within themeter body, which being of magnetic material (steel), perform the corefunction of the iron laminations previously required, thereby effectinga marked reduction in the size and weight of the meter.

A meter of the type shown in FIG. 1 operates efficiently as long as theliner is in good condition, but when liner 18 is degraded by abrasiveparticles or by other properties of the fluid being measured, it isnecessary to return the meter to the factory in order to replace thedefective liner. The present invention makes it possible to quicklyreplace the liner on the job site.

In a meter according to the invention, the meter body as shown in FIG.2, is constituted by a cylindrical pipe section 21 of magnetic materialhaving a flange 22 secured to one end thereof and a flange 23 secured tothe other end thereof. The inner diameters of the flanges are smallerthan that of the pipe section 21, thereby defining an annular channel toaccommodate the coils and potting compound 24. Flange 22 is providedwith an annular step 22A which is displaced outwardly relative to thecylindrical inner surface of potting compound 24, whereas flange 23 isprovided with an annular step 23A which is inwardly displaced relativeto said inner surfaces.

In practice, annular step 23A may be defined by a removable ring whichis adapted to fit into a circular groove in the flange. This allows moreroom for the insertion of the collapsed end of the liner assembly. Thering is slipped over the collapsed end after the liner assembly is inplace.

Telescopically receivable within the meter body is a liner assembly inaccordance with the invention. This assembly, as shown in FIG. 3consists of a cylindrical metal sleeve 25 of non-magnetic material suchas aluminum or stainless steel, having a metal flange 26 secured to onlyone end thereof. Flange 26 is provided with a shoulder 26A which nestswithin step 22A on flange 22 when the line assembly is in place, whereasthe flange-free end of sleeve 25 is accommodated within step 23A offlange 23 of the meter body. Thus when the sleeve is inserted, it issnugly socketed within the meter body.

Disposed concentrically within sleeve 25 is a tubular liner 27 having aflange 28 at one end thereof, which abuts the face of sleeve flange 26and is bonded thereto, the other end of liner 27 having a flange 29formed thereon that is adapted to lie against the face of meter bodyflange 23 when the liner assembly is in place.

Liner 27 is composed of polyurethane or any other suitable resilientmaterial having good electrical insulating properties, such as Teflon.The liner is bonded to the inner wall of sleeve 25, except in the endportion thereof which includes flange 29.

In order to be able to insert the liner assembly within the meter body,it is necessary to collapse the end portion of the liner, for otherwiseliner flange 29 will prevent insertion through the body passage. Forthis purpose, a tool is useful. The tool is in the form of a ring 30which is dimensioned to slide within the flange-frec end of sleeve 25and to collapse the end portion of the liner, so that when the ring 30is pushed into the sleeve, the flange 29 of the liner is compressedwithin the ring, thereby making it possible to telescope the linerassembly within the meter body. Once the liner assembly is inserted,ring 30 is withdrawn and the collapsed liner flange 29 is free to snapout against the face of body flange 23.

When the liner assembly is fully inserted in the meter body, it is heldthereto by means of bolts 31 which pass through registered bores inassembly flange 26 and body flange 22 as shown in FIG. 6. Should itthereafter become necessary to replace the liner assembly on the jobsite, these bolts are taken out, the electrodes are removed, and theassembly is then pulled out without difficulty.

Meter body 21 and the liner assembly are each provided with a pair ofregistered apertures at diametrically opposed positions, one meter bodyaperture 21A being shown in FIG. 2, and one assembly aperture 25A beingshown in FIG. 3. These apertures accommodate the meter electrodes whichare inserted therein from the inside of the assembly.

Thus, as shown in FIG. 7, the electrode 32 is provided with a headportion 32A and a shank portion 328, the head portion resting within arecess formed in liner 27 and being provided at its inner face with anO- ring 33 or flat gasket 35 to seal the electrode and to prevent fluidseepage into the bore receiving the electrode. Shank 32B passes throughmetal sleeve 25 and is insulated therefrom by a bushing 34. An O-ringseal 36 is located above bushing 34.

Electrode head 32A is provided with two holes 37 for a spanner wrench sothat the electrode can be prevented from rotating when tightening thenut. These holes can also be used to indicate the amount of headmaterial being worn away.

While there has been shown and described a preferred embodiment of anelectromagnetic flowmeter having a removable liner in accordance withthe invention, it will be appreciated that many changes andmodifications may be made therein without, however, departing from theessential spirit of the invention. Thus instead of having electrodeswhose heads protrude from the liner, the liner may be provided withrecessed seats molded therein to accommodate the heads so that only thefaces thereof would be exposed, thereby minimizing erosion of the heads.Or the electrodes may be in the form of metal discs or buttons embeddedin the liner with only the faces exposed, in which event instead ofelectrode stems, wires would be connected directly to the buttons.

We claim:

1. In combination with an electromagnetic flowmeter having a pipeprovided at either end with a coupling flange, a replaceable linerassembly comprising:

A. a sleeve of relatively rigid non-magnetic material, having a flangeat only one end thereof which when the assembly is inserted, liesagainst the corresponding flange on the pipe, and

B. a tubular liner of resilient insulating material concentricallydisposed within said sleeve, said liner having a first flange whichabuts the flange of the sleeve and a second flange adapted to abut thecorresponding flange on the pipe, said liner being bonded to said sleeveexcept at the end portion thereof which includes said second flange,whereby the end portion may be collapsed to permit insertion of theassembly in said pipe.

2. A liner assembly as set forth in claim 1, wherein said liner isformed of polyurethane.

3. A liner assembly as set forth in claim 1 wherein said sleeve isformed of stainless steel.

4. A liner assembly as set forth in claim 1, wherein said sleeve isformed of aluminum.

5. A flowmeter combination as set forth in claim 1, further including asassembling ring insertable in said sleeve to effect collapse of said endportion.

6. An electromagnetic flowmeter comprising:

A. a pipe of magnetic material having coupling flanges on either endthereof to define between said flanges an annular channel;

B. coils disposed in said annular channel to establish anelectromagnetic field at right angles to the longitudinal axis of thepipe;

C. a pair of electrodes disposed at diametrically opposed positions onsaid pipe; and

D. a replaceable liner assembly telescopable within said pipe, saidassembly being constituted by a sleeve of non-magnetic material having aflange only at one end thereof, which when the sleeve is inserted, liesagainst the corresponding pipe flange, and a tubular liner of resilientinsulating material concen rically dispog ed within said sleeve, saidliner aving a first ange at one end which lies against the sleeveflange, and a second flange at the other end adapted to lie against thecorresponding pipe flange, said liner being bonded to said sleeve exceptat the end portion which includes the second flange whereby the endportion may be collapsed to permit entry of the assembly in said pipe.

7. A flowmeter as set forth in claim 6, wherein said sleeve is formed ofstainless steel.

8. A flowmeter as set forth in claim 6, wherein said liner is formed ofpolyurethane.

9. A flowmeter as set forth in claim 6, wherein said electrodes areprovided with heads embedded in or recessed in said liner whereby onlythe faces thereof are exposed to fluid.

1. In combination with an electromagnetic flowmeter having a pipeprovided at either end witH a coupling flange, a replaceable linerassembly comprising: A. a sleeve of relatively rigid non-magneticmaterial, having a flange at only one end thereof which when theassembly is inserted, lies against the corresponding flange on the pipe,and B. a tubular liner of resilient insulating material concentricallydisposed within said sleeve, said liner having a first flange whichabuts the flange of the sleeve and a second flange adapted to abut thecorresponding flange on the pipe, said liner being bonded to said sleeveexcept at the end portion thereof which includes said second flange,whereby the end portion may be collapsed to permit insertion of theassembly in said pipe.
 2. A liner assembly as set forth in claim 1,wherein said liner is formed of polyurethane.
 3. A liner assembly as setforth in claim 1 wherein said sleeve is formed of stainless steel.
 4. Aliner assembly as set forth in claim 1, wherein said sleeve is formed ofaluminum.
 5. A flowmeter combination as set forth in claim 1, furtherincluding as assembling ring insertable in said sleeve to effectcollapse of said end portion.
 6. An electromagnetic flowmetercomprising: A. a pipe of magnetic material having coupling flanges oneither end thereof to define between said flanges an annular channel; B.coils disposed in said annular channel to establish an electromagneticfield at right angles to the longitudinal axis of the pipe; C. a pair ofelectrodes disposed at diametrically opposed positions on said pipe; andD. a replaceable liner assembly telescopable within said pipe, saidassembly being constituted by a sleeve of non-magnetic material having aflange only at one end thereof, which when the sleeve is inserted, liesagainst the corresponding pipe flange, and a tubular liner of resilientinsulating material concentrically disposed within said sleeve, saidliner having a first flange at one end which lies against the sleeveflange, and a second flange at the other end adapted to lie against thecorresponding pipe flange, said liner being bonded to said sleeve exceptat the end portion which includes the second flange whereby the endportion may be collapsed to permit entry of the assembly in said pipe.7. A flowmeter as set forth in claim 6, wherein said sleeve is formed ofstainless steel.
 8. A flowmeter as set forth in claim 6, wherein saidliner is formed of polyurethane.
 9. A flowmeter as set forth in claim 6,wherein said electrodes are provided with heads embedded in or recessedin said liner whereby only the faces thereof are exposed to fluid.